Diffusion tensor free water MRI predicts progression of FLAIR white matter hyperintensities after ischemic stroke

Background The progression of FLAIR white matter hyperintensities (WMHs) on MRI heralds vascular-mediated cognitive decline. Even before WMH progression, adjacent normal appearing (NAWM) already demonstrates microstructural deterioration diffusion tensor imaging (DTI). We hypothesized that elevated DTI free water (FW) would precede implicating interstitial fluid accumulation as a key pathological step in the cerebral small vessel disease. Methods Participants at least 3 months after an ischemic stroke or TIA with underwent serial brain MRIs every over subsequent year. For each participant, WMHs were automatically segmented, aligned, and region penumbra tissue risk was defined by dilating lesions any time point subtracting baseline lesions. Penumbra voxels classified either stable progressing to if they segmented new demonstrated increasing intensity time. Aligned images included FW FW-corrected fractional anisotropy (FA Tissue ) mean diffusivity (MD ). Logistic regression area under receiver-operator characteristic curve (AUC) used test whether predicted voxel-wise classification while covarying for clinical factors. Results In participants ( n = 26, age 71 ± 9 years, 31% female), we detected median annual growth 2.9 2.6 ml. Each metric associated lesion penumbra, but had greatest AUC 0.732 (0.730 – 0.733) predicting pooled across participants. Discussion Baseline increased fluid, estimated DTI, NAWM following These results implicate presence pathogenesis disease progression.